Paperboard runners and paperboard pallets constructed therewith

ABSTRACT

Broadly, the present invention is directed to paperboard runners and paperboard pallets constructed therewith. One aspect of the invention comprises a paperboard pallet comprising an upper deck and a lower deck having a plurality of runners interposed therebetween and affixed to each of said decks. Each of the runners comprises a sheet of paperboard that has been folded into a rectangular form having top and bottom walls, a pair of sidewalls, and a central vertical wall (e.g., the two ends of the sheet pressed together) interposed between the sidewalls. The top wall has openings. The central wall has quarter-round cut-outs located at the longitudinal ends of the top wall cut-out areas. The top wall openings are adapted to receive flaps having central slots cut in them. The flaps are selected from: flaps formed from said runner top wall; flaps cut from an upper deck attached to said runner; or flaps formed from a rectangular insert which has a pair of end slotted flaps, which insert fits into said top wall opening with said end slotted flaps folding downwardly into said quarter-round cut-outs. Another aspect of the present invention comprises the runners described herein. 
     A further aspect of the present invention is an alternate paperboard runner which comprises a sheet of paperboard that has been folded into a rectangular form by one end being folded to form a first bottom wall, a first sidewall, a first top wall, and a second sidewall; and the other end being folded into an &#34;S&#34; configuration to form a central vertical wall, a part second top wall which lays against said first top wall, and a part second bottom wall which lays against said first bottom wall. The top wall has openings. The central vertical wall has quarter-round cut-outs located at the longitudinal ends of said top wall cutout areas. The top wall openings are adapted to receive flaps which have central slots cut in them. The flaps are selected from: flaps formed from said runner top wall; flaps cut from an upper deck attached to said runner; or flaps formed from a rectangular insert which has a pair of end slotted flaps which insert fits into said top wall opening with said end slotted flaps folding downwardly into said quarter round cut-outs. This paperboard pallet embodiment can be made collapsible for shipment and storage, yet it can be simple and quickly assembled into a strong, lightweight, disposable pallet.

BACKGROUND OF THE INVENTION

The present invention generally relates to pallets and more particularlyto an improved paperboard pallet made using novel paperboard runners.

Pallets have been made for many years completely of wood and suchpallets ordinarily are re-used a number of times. Thereafter, however,the wood pallets must be disposed of in an acceptable manner. Thisdisposal problem is magnified when large assembly plants, e.g.automobile assembly plants, are considered since thousands of woodpallets must be disposed of in an acceptable manner.

The art, then, has turned to disposable pallets made of corrugatedpaper. Such paperboard pallets, however, have not been found to begenerally satisfactory, being deficient in areas including lateralstability and cost. Moreover, such paperboard pallets must be capable ofbeing moved by conventional forklift trucks.

Such prior paperboard pallets can be exemplified by U.S. Pat. No.2,997,266 which proposes a pallet structure wherein U-shaped wood blockmembers provide structural rigidity to each of the paperboard beams.U.S. Pat. No. 3,000,603, calls for tabs to be inserted into rectangularopenings in the beams and engage slots in a central vertical wall. U.S.Pat. No. 3,601,067 utilizes reinforced legs and collars for the palletstructure. U.S. Pat. No. 3,659,534 provides for S-shaped folds at theend of each sheet in order to provide structure for the pallet. U.S.Pat. No. 4,100,859 utilizes "egg-carton" type inserts for providingrigidity to the forklift pallet. U.S. Pat. No. 4,303,020 utilizes woodstiffening elements in the paperboard pallet while U.S. Pat. No.4,563,377 provides a folded beam structure. U.S. Pat. No. 4,714,026provides blocks for reinforcing the beams that support the pallet. U.S.Pat. No. 4,802,421 provides circular cross elements for stiffening ofthe lateral beams. U.S. Pat. No. 4,936,229 provides for a grid ofslotted vertical members for providing rigidity to the pallet. U.S. Pat.No. 5,001,991 provides a cross beam structure of folded cardboard forconstruction of a pallet.

Despite the art on paperboard pallets, load bearing capability, lateraldeflection strength, and economy of cost are a combination of factorsthat have eluded the art. Moreover, a truly collapsible paperboardpallet has yet to be proposed.

BROAD STATEMENT OF THE INVENTION

Broadly, the present invention is directed to paperboard runners andpaperboard pallets constructed therewith. One aspect of the inventioncomprises a paperboard pallet comprising an upper deck and a lower deckhaving a plurality of runners interposed therebetween and affixed toeach of said decks. Each of the runners comprises a sheet of paperboardthat has been folded into a rectangular form having top and bottomwalls, a pair of sidewalls, and a central vertical wall (e.g., the twoends of the sheet pressed together) interposed between the sidewalls.The top wall has cut-out areas or openings. The central wall hasquarter-round cut-outs located at the longitudinal ends of the top wallcut-out areas. The top wall cut-out areas are adapted to receive flapshaving central slots cut in them. The flaps are selected from: flapsformed or cut from said runner top wall; flaps formed or cut from anupper deck attached to said runner; or flaps cut from a rectangularinsert which has a pair of end slotted flaps, which insert fits intosaid top wall cut-out with said end slotted flaps folding downwardlyinto said quarter-round cut-outs. Another aspect of the presentinvention comprises the runners described herein.

A further aspect of the present invention is an alternate paperboardrunner which comprises a sheet of paperboard that has been folded into arectangular form by one end being folded to form a first bottom wall, afirst sidewall, a first top wall, and a second sidewall; and the otherend being folded into an "S" configuration to form a central verticalwall, a part second top wall which lays against said first top wall, anda part second bottom wall which lays against said first bottom wall. Thetop wall has cut-out areas or openings. The central vertical wall hasquarter-round cut-outs located at the longitudinal ends of said top wallcut-out areas. The top wall cut-out areas are adapted to receive flapswhich have central slots cut in them. The flaps are selected from: flapsformed or cut from said runner top wall; flaps formed or cut from anupper deck attached to said runner; or flaps cut from a rectangularinsert which has a pair of end slotted flaps which insert fits into saidtop wall cut-out with said end slotted flaps folding downwardly intosaid quarter round cut-outs. This paperboard pallet embodiment can bemade collapsible for shipment and storage, yet it can be simple andquickly assembled into a strong, lightweight, disposable pallet.

Yet another paperboard pallet embodiment comprises a sheet of paperboardthat has been folded into a rectangular form having top and bottomwalls, a pair of sidewalls, and a central vertical wall interposedbetween said sidewalls. The top wall has cut-out areas or openings. Thecentral wall has slots located at the longitudinal ends of said top wallcut-out areas. The top wall cut-out areas are adapted to receive aU-shaped insert which has a pair of end slotted flaps, which insert fitsinto said top wall cut-out area with said end slotted flaps foldingdownwardly into said central wall slots.

Advantages of the present invention include paperboard pallets that areinexpensive to produce. A further advantage are paperboard pallets thatcan bear heavy loads, yet still possess lateral stability. Anotheradvantage is a paperboard pallet construction that is collapsible forstorage and shipment, yet which can be assembled rapidly and easily foruse. Yet a further advantage are paperboard pallets which can be readilyand environmentally recycled. These and other advantages will becomereadily apparent to those skilled in the art based upon the disclosurecontained herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of one embodiment of the pallet of thepresent invention;

FIG. 2 is a cross-sectional elevational view taken along line 2--2 ofFIG. 1;

FIG. 3 is a cross-sectional elevational view taken along line 3--3 ofFIG. 2;

FIG. 4 is a top perspective view of one embodiment of the pallet runnerof the present invention;

FIG. 5 is a plan view of the blank from which the pallet runner of FIG.4 is formed;

FIG. 6 is a plan view of the insert adapted to be used with the palletrunner of FIG. 4;

FIG. 7 is a top perspective view of another embodiment of the pallet ofthe present invention;

FIG. 8 is a top perspective view of the pallet of FIG. 7 in itscollapsible position for transport and storage;

FIG. 9 is a cross-sectional elevational view taken along line 9--9 ofFIG. 7;

FIG. 10 is a cross-sectional elevational view taken along line 10--10 ofFIG. 9;

FIG. 11 is a cross-sectional elevational view taken along line 11--11 ofFIG. 9;

FIG. 12 is a top perspective view of the pallet runner used inconstructing the novel pallet of FIG. 7;

FIG. 13 is a plan view of the blank from which the pallet runner of FIG.12 can be formed;

FIG. 14 is a cross-sectional elevational view like that of FIG. 9 butshowing an alternative construction embodiment;

FIG. 15 is a cross-sectional elevational view, like that of FIGS. 9 and14, but showing yet another pallet runner embodiment; and

FIG. 16 is a cross-sectional elevational view taken along line 16--16 ofFIG. 15.

The drawings will be described in detail below.

DETAILED DESCRIPTION OF THE INVENTION

The basic paperboard pallet construction of pallet 8 can be seen in FIG.1 to be composed of top wall 10, bottom wall 12, and paperboard runners14, 16, and 18 which are interposed between sheets 10 and 12 and areaffixed thereto, preferably by application of adhesive. While threepaperboard runners are shown in the pallet of FIG. 1, it will beappreciated that, depending upon the size and load requirements, a fewernumber (e.g. 2) or a greater number of paperboard runners could be used.It will be observed that the space formed between runners 14 and 16, andrunners 16 and 18 provides access for a forklift truck to engage pallet8 for lifting and moving it. In this regard, also, it will beappreciated that pallet runner 14 has openings 20 and 22 for convertingthe pallet into a four-way entry pallet; thus, permitting the forkliftoperator to access the pallet from any direction (similar openings beingmade in runner 18 which openings are not shown in the drawings). Runner16 has openings 21 and 23 (FIG. 4), though the forks of the forklift maynot reach such openings. By providing all runners with such sideopenings, any runner can be placed at any exterior or interior positionbetween decks 10 and 12.

With respect to the paperboard runners themselves, the followingdescription is of runner 16, though the description is illustrative ofrunners 14 and 18. With respect to FIGS. 1-3, it will be seen thatrunner 16 is formed from double-wall paperboard as are top deck 10 andbottom deck 12. In this regard, it will be appreciated that all of thecomponents may be constructed from single-wall paperboard, double-wallpaperboard, or higher wall construction. In fact, different componentscan be constructed from paperboard of different thicknesses, dependingupon requirements of the components. Thus, the number of plies ofpaperboard referred to herein is by way of illustration and notlimitation.

The sheet from which runner 16 is made (FIG. 5) is suitably scored andfolded to produce the structure depicted at FIG. 3 wherein each of theends (e.g., ends 25 and 27) mates to form vertical, central wall 24.Sidewalls 29 and 31 and top wall 33 are continuously formed while bottomwall 35 is composed of two individual segments in abutting relationship.Additionally, FIG. 2 reveals quarter-round cut-outs, i.e. 26 and 28, incentral wall 24 of runner 16. It, further, will be appreciated from FIG.2 that an opening, e.g. opening 37, has been created in top wall 33 ofrunner 16 as revealed further in FIG. 4. Opening 37, and other openings,have been created by die cutting and scoring of sheet 30 (FIG. 5) toform slotted flaps 32a and 32b. Slotted flaps 32a and 32b can be foldeddownwardly and inwardly into runner 16 though opening 37 with the slotsin flaps 32a and 32b traversing quarter-round cut-outs 26 and 28 untilflaps 32a and 32b are oriented in a vertical position for providingadditional strength to runner 16. It will be observed that quarter-roundcut-outs 26 and 28 are very important as the outer edge of flaps 32a and32b pivot around score lines 36 and 34, respectively, which necessarilymakes them traverse an arc of a circle having its center along the scorelines. Were cut-outs 26 and 28 missing, flaps 32a and 32b would not beable to be folded down into position after sheet 38 was folded intofinal configuration. Assembly clearly is rendered facile by the use ofcut-outs 26 and 28. Note also that openings 21 and 23 can be seen to bedie cut into the blank depicted at FIG. 5.

While the construction thus far described provides a runner highlysuitable for construction of sturdy, durable pallets, additionalstrength (especially resistance to rolling or lateral deflection of thepallet) can be gained by use of insert 38 (FIGS. 4 and 6). Insert 38 isU-shaped and is formed to contain a pair of slotted ends which fit intothe opening 37 created after flaps 32a and 32b are folded downwardly,and the slotted ends of insert 38 similarly engage central wall 24 justinwardly from flaps 32a and 32b. Additionally, the top surface of insert38 gives runner 16 a continuous top without openings. Thus, a highlydurable, unique, yet easy to assemble pallet and pallet runner have beendisclosed. A double wall pallet constructed like that shown in FIGS. 1-5without inserts like insert 38 was found to withstand a load of 16,860pounds, while the addition of inserts like insert 38 increased the loadcapacity to 19,050 pounds.

Pallet 8 is constructed at the plant and shipped to the customer inassembled form. Pallet 40 (FIGS. 7-14), however, is constructed forshipping and storage in collapsed form as depicted at FIG. 8. Pallet 40can be seen to be composed of top deck 42 and bottom deck 44 which decksalso are of double wall thickness in construction, though single wall,or additional wallpaper plies could be used as is necessary, desirable,or convenient. Pallet 40 can be seen to have interposed between decks 42and 44, paperboard runners 46, 48, and 50. As with runner 16, thecentral vertical wall in runner 48 (typical of runners 46 and 50 also)contain quarter-round cut-outs 52 and 54 (FIG. 9) which enable flaps 56aand 56b (FIGS. 9 and 13) to be folded down into runner 48. In similarfashion, insert 58 with slotted ends also can be inserted though opening45 (FIG. 8) for adding additional strength to pallet 40.

Because runner 48 is formed in a different manner than runner 16,central wall 51 is formed from only one end of the sheet as can be seenby reference to FIGS. 12 and 13. Bottom wall 53, sidewalls 55 and 59,and top wall 57 and formed from one end of the blank shown at FIG. 13,while the other end is folded into an S-shape for forming partial bottomwall 53 which lays flat against bottom wall 53, vertical wall 51, andpartial top wall 63 which lays flat against top wall 57.

The pattern laid out for runner 48 in unassembled state as depicted atFIG. 13 reveals flaps 64 and 66 which are in juxtaposition with openings68/70 and 72/74, respectively, and which can be opened manually or by aforklift which engages the side of runner 46 to open such flaps die cutin runner 48. Such flaps provide additional vertical structural supportto paperboard pallet 40. Runner 48 may not have flaps 64 and 66 pushedinwardly to form openings depending upon the length of the forks of theforklift and the degree of insertion into pallet 40. Openings 60 and 62in runner 46, however, will be opened if the forklift approached pallet40 from the side. Similar flaps for forming forklift openings areprovided in runner 50 to make pallet 48 a four-way pallet also.

While FIG. 9 shows flaps 56a and 56b formed in top wall 57 of runner 48being folded downwardly to engage central vertical wall 51, FIG. 14shows an alternate embodiment wherein top deck 42 has been die cut andscored to create flaps 76 and 78 for folding down into opening 65 inrunner 48 which has been die cut to remove flaps 56a and 56b to createan opening top wall 57. Thus, collapsible pallet 40 can be held in anassembled, rigid condition as depicted at FIG. 7 by folding flaps downfrom the top wall of runner 48, insert 58, or top deck 42, or evencombinations thereof.

An alternative construction for collapsible runner 40 is set forth atFIGS. 15 and 16. In this instance, inserts 58 fit into vertical slots 80and 82 which are cut into central wall 51. In such embodiment, however,flaps from top deck 42 and from top wall 57 of runner 48 cannot bepresent as quarter-round cut-outs 52 and 54 are absent and have beenreplaced by slots 80 and 82. Such embodiment is not as facile toassemble from its dormant state as depicted at FIG. 8 to its assembledstate at FIG. 7, though such embodiment clearly is within the preceptsof the present invention.

It will be appreciated that additional modifications and changes may bemade to the pallet runners and pallets disclosed herein, yet suchchanges still are within the spirit and precepts of the inventiondisclosed herein and are considered to be part of the disclosure andinvention disclosed and claimed herein.

We claim:
 1. A paperboard blank having an outer periphery defining awidth and a longitudinal extent and configured for foldable assemblyinto a runner having a top wall with at least one opening of a givenwidth and longitudinal extent, a pair of parallel side wallsperpendicular to said top wall, a bottom wall parallel to said top wall,a central wall parallel to and intermediate said side walls, and atleast two flaps disposed perpendicular to said central wall at oppositelongitudinal ends of said top wall opening and having central slotsconfigured for retaining said central wall therewithin, said flapsselected from (a) flaps .[.provided with.]. .Iadd.formed from.Iaddend.said runner top wall, (b) flaps provided with an upper deckattached to said runner, (c) flaps provided with .[.a rectangular.]..Iadd.an .Iaddend.insert which has a pair of end slotted flaps whichinsert fits into said top wall opening with said end slotted flapsfolding downwardly over said central wall, or (d) combinations thereof,said blank comprising:a central pair of parallel fold lines disposed ina spaced apart relationship to define therebetween a top wall portionfor forming said top wall, said top wall portion having at least oneopening portion for forming said top wall opening; a second pair ofparallel fold lines spaced outwardly from and parallel to said centralpair of parallel fold lines to define therewith a pair of side wallportions for forming said side walls; a third pair of parallel foldlines spaced outwardly from and parallel to said second pair of parallelfold lines intermediate said outer periphery to define with said secondpair of parallel fold lines a pair of bottom wall portions for formingsaid bottom wall and to define with said outer periphery a pair ofcentral wall portions for forming said central wall, said central wallportions each having a pair of .[.quarter-round.]. cut-outs disposed formutual registry at the longitudinal ends of said top wall opening andconfigured to enable the folding of said flaps over said central wall.2. The paperboard blank of claim 1 which additionally has openings ineach of said sidewall portions disposed for registry so that the fork ofa forklift can penetrate therethrough.
 3. The paperboard blank of claim1 wherein said flaps are .[.provided with.]. .Iadd.formed from.Iaddend.said runner top wall portion.
 4. The paperboard blank of claim1 wherein said flaps are .[.provided with a rectangular.]. .Iadd.formedfrom an .Iaddend.insert which has a pair of end slotted flaps whichinsert fits into said top wall portion opening, said end slotted flapsfolding downwardly into said .[.quarter-round.]. cut-outs.
 5. Apaperboard pallet comprising a top deck and bottom deck having multiplerunners interposed therebetween and attached thereto, said runnerscomprising a sheet of paperboard that has been folded into a rectangularform by(a) one end being folded to form a first bottom wall, a firstside wall, a first top wall, and a second side wall; and (b) the otherend being folded in an "S" configuration to form a central verticalwall, a part second top wall which lays against said first top wall, anda part second bottom wall which lays against said first bottom wall;said top wall having openings, .[.said central vertical wall havingquarter-round cutouts located at the longitudinal ends of said top wallopenings;.]. said top wall openings receiving flaps which have centralslots cut in them, said flaps selected from (a) flaps .[.providedwith.]. .Iadd.formed from .Iaddend.said runner top wall, (b) flapsprovided with an upper deck attached to said runner, (c) flaps providedwith .[.a rectangular.]. .Iadd.an .Iaddend.insert which has a pair ofend slotted flaps which insert fits into said top wall opening with saidend slotted flaps folding downwardly into said .[.quarter-roundcut-outs.]. .Iadd.central wall, .Iaddend.or (d) combinations thereof. 6.The paperboard pallet of claim 5 wherein said flaps are not engaged insaid central wall .[.quarter-round cut-outs.]. so that said pallet is ina collapsed state.
 7. The paperboard pallet of claim 5 wherein saidflaps are engaged in said central wall .[.quarter-round cut-outs.]. sothat said pallet is in a rigid formed state for use.
 8. The paperboardpallet of claim 5 which additionally has openings in each of saidsidewalls disposed in registry so that the fork of a .[.forklike.]..Iadd.forklift .Iaddend.penetrate therethrough.
 9. The paperboard palletof claim 5 wherein said flaps are .[.provided with.]. .Iadd.formed from.Iaddend.said runner top wall.
 10. The paperboard pallet of claim 5wherein said flaps are .[.provided with a rectangular.]. .Iadd.formedfrom an .Iaddend.insert which has a pair of end slotted flaps whichinsert fits into said top wall cut-out with said end slotted flapsfolding downwardly into said .[.quarter-round cutouts.]. .Iadd.centralwall. .Iaddend.
 11. The paperboard pallet of claim 5 wherein said flapsare a combination of (a) and (c).
 12. The paperboard pallet of claim 5wherein .[.U-shaped.]. inserts having a pair of oppositely-disposed, endslotted flaps are inserted into said top wall openings and said slottedflaps engage said central wall .[.quarter-round cut-outs.]..
 13. Apaperboard pallet comprising an upper deck and a lower deck having aplurality of runners interposed therebetween and affixed to each of saidsheets, each of said runners comprising a sheet of paperboard that hasbeen folded into a rectangular form having top and bottom walls, a pairof side walls, and a central vertical wall interposed between said sidewalls; the top wall having cut-out areas, the central wall having slotslocated at the longitudinal ends of said top wall cut-out areas; saidtop wall cut-out areas receiving .[.a U-shaped.]. .Iadd.an .Iaddend.aninsert which has a pair of end slotted flaps which insert fits into saidtop wall cut-out area with said end slotted flaps folding downwardlyinto said central wall slots.
 14. A paperboard runner, suitable for usein forming a paperboard pallet composed of a top and bottom sheet havingmultiple runners interposed therebetween and attached thereto, whichcomprises: a sheet of paperboard that has been folded into a rectangularform having top and bottom walls, a pair of side walls, and a centralvertical wall .[.provided with.]..Iadd.formed from .Iaddend.ends of saidsheet and interposed between said side walls; the top wall havingopenings, .[.the central wall having quarter-round cut-outs located atthe longitudinal ends of said top wall openings;.]. said top wallopenings receiving flaps having central slots cut in them, said flaps acombination of (a) flaps .[.provided with.]. .Iadd.formed from.Iaddend.said runner top wall, and (b) flaps provided with .[.arectangular.]. .Iadd.an .Iaddend.insert which has a pair of end slottedflaps which insert fits into said top wall opening with said end slottedflaps folding downwardly into said .[.quarter-round cut-outs.]..Iadd.central wall. .Iaddend.
 15. A paperboard runner, suitable for usein forming a paperboard pallet composed of a top and bottom sheet havingmultiple runners interposed therebetween and attached thereto, whichcomprises:a sheet of paperboard that has been folded into a rectangularform having top and bottom walls, a pair of side walls, and a centralvertical wall .[.provided with.]. .Iadd.formed from .Iaddend.ends ofsaid sheet and interposed between said side walls; the top wall havingopenings, .[.the central wall having quarter-round cut-outs located atthe longitudinal ends of said top wall openings;.]. said top wallopenings receiving flaps having central slots cut in them, said flapsselected from (a) flaps .[.provided with.]. .Iadd.formed from.Iaddend.said runner top wall, (b) flaps provided with an upper deckattached to said runner, (c) flaps provided with .[.a rectangular.]..Iadd.an .Iaddend.insert which has a pair of end slotted flaps whichinsert fits into said top wall opening with said end slotted flapsfolding downwardly into said .[.quarter-round cut-outs.]. .Iadd.centralwall, .Iaddend.or (d) combinations thereof; and .[.U-shaped.]. insertshaving a pair of oppositely disposed slotted flaps inserted into saidtop wall openings, said slotted flaps engaging said central wall.[.quarter-round cut-outs.]..
 16. A paperboard pallet comprising anupper deck and a lower deck having a plurality of runners interposedtherebetween and affixed to each of said decks, each of said runnerscomprising a sheet of paperboard that has been folded into a rectangularform having top and bottom walls, a pair of side walls, and a centralvertical wall interposed between said side walls; the top wall havingopenings, .[.the central wall having quarter-round cut-outs located atthe longitudinal ends of said top wall openings;.]. said top wallopenings receiving flaps having central slots cut in them, said flaps acombination of (a) flaps .[.provided with.]. .Iadd.formed from.Iaddend.said runner top wall, and (b) flaps provided with .[.arectangular.]. .Iadd.an .Iaddend.insert which has a pair of end slottedflaps which insert fits into said top wall opening with said end slottedflaps folding downwardly into said .[.quarter-round cut-outs.]..Iadd.central wall.Iaddend..
 17. A paperboard pallet comprising:an upperdeck; a lower deck; a plurality of runners interposed between andaffixed to each of said decks, each of said runners comprising a sheetof paperboard that has been folded into a rectangular form having topand bottom walls, a pair of side walls, and a central vertical wallinterposed between said side walls; the top wall having openings, .[.thecentral wall having quarter-round cut-outs located at the longitudinalends of said top wall openings;.]. said top wall openings receivingflaps having central slots cut in them, said flaps selected from (a)flaps .[.provided with.]. .Iadd.formed from .Iaddend.said runner topwall; (b) flaps provided with an upper deck attached to said runner; (c)flaps provided with .[.a rectangular.]. .Iadd.an .Iaddend.insert whichhas a pair of end slotted flaps which insert fits into said top wallopening with said end slotted flaps folding downwardly into said.[.quarter-round cut-outs.]. .Iadd.central wall, .Iaddend.or (d)combinations thereof; and .[.U-shaped.]. inserts having a pair ofoppositely-disposed, end slotted flaps inserted into said top wallopenings, said slotted flaps engaging said central wall .[.quarter-roundcut-outs.]..